Method and system of performing incremental SQL server database backups

Abstract

A system, method, and medium for performing incremental backups of a Microsoft SQL server database. A snapshot of the database is created, and then a map identifying the changed extents is retrieved from the snapshot. The changed extents are then retrieved from the snapshot and stored in a backup storage device. For a restore operation, a full database backup file is written to a storage device and then the changed extents from a stored incremental backup file may be merged with the full backup file. Next, the database server is notified of the reconstructed file and then the reconstructed file is mounted by the database server as a live instance of the database.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates generally to database backups, and in particular to a method and system for performing incremental backups of a SQL server database.[0003]2. Description of the Related Art[0004]Database systems, such as a Microsoft® structured query language (SQL) server database system, contain vast amounts of information generated and used by a variety of software applications. Because of the importance of the information stored in databases, a database system provides mechanisms to back up and restore the databases managed by that system. A backup mechanism may create a complete copy of the database, and the restore mechanism may overwrite the database with the copy. A database system may also be capable of playing back transactions to restore a database. Such a database system may log all transactions and use those transactions to restore a database to a particular state by starting at a known prior sta...

AI Technical Summary

Benefits of technology

[0017]In another embodiment, a restore operation may be requested following one or more incremental backups. A media server may retrieve a prior full backup file from a backup storage device and write the prior full backup file to a storage device, such as a disk or other storage device associated with the media server or the SQL server. The media server may perform this step without requiring any input from the SQL server. This may allow the SQL server to continue performing operations as part of the normal functionality of the database, such as processing new transactions. Next, the media server may retrieve one or more incremental backup files and write the changed extents from the incremental backup files to the appropriate locations within the full backup file. The media server may write changed extents to the full backup file from a plurality of incremental backup files; the plurality of incremental backup files may correspond to a plurality of incremental backups that were performed following the full backup operation. The media server may also write changed extents from the incremental backup files in the order they were created, such that changed extents from the oldest incremental backup file are written first, and changed extents from the newest incremental backup file are written last. The media server may determine where the changed extents belong in the unmounted full backup file by reading the one or more maps that were stored as part of the incremental backup operation. The media server may write the changed extents back within the unmounted full backup file without requiring any input from the SQL server.

Problems solved by technology

When a database file is mounted by a SQL server, and when the size of the database file needs to increase beyond the size allocated to it to accommodate new transactions, it is a time-consuming process to increase the size of the database.

However, when performing a full backup, all of the space allotted to the database, even if it is not being used, will be backed up, thus increasing the size of backups.

For example, a differential backup must be restored to a live instance of the database, which will result in downtime of the database.

However, SQL server currently does not support incremental backups of the database.

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